The NGC 300 Transient: An Alternative Method For Measuring Progenitor Masses (2009)
Gogarten, Stephanie M., Dalcanton, Julianne J., Murphy, Jeremiah W., Williams, Benjamin F., Gilbert, Karoline, Dolphin, Andrew
We present an alternative technique for measuring the precursor masses of transient events in stars undergoing late stage stellar evolution. We use the well-established techniques of stellar...
The ACS Nearby Galaxy Survey Treasury (2009)
Dalcanton, Julianne J., Williams, Benjamin F., Seth, Anil C., Dolphin, Andrew, Holtzman, Jon, Rosema, Keith, ...
The ACS Nearby Galaxy Survey Treasury (ANGST) is a systematic survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D14...
A Panoply of Cepheid Light Curve Templates (2009)
Yoachim, Peter, McCommas, Les P., Dalcanton, Julianne J., Williams, Benjamin F.
We have generated accurate V and I template light curves using a combination of Fourier decomposition and principal component analysis for a large sample of Cepheid light curves. Unlike previous...
The ACS Nearby Galaxy Survey Treasury III: Cepheids in the Outer Disk of M81 (2009)
McCommas, Les P., Yoachim, Peter, Williams, Benjamin F., Dalcanton, Julianne J., Davis, Matthew R., Dolphin, Andrew E.
The ACS Nearby Galaxy Survey Treasury (ANGST) has acquired deep ACS imaging of a field in the outer disk of the large spiral galaxy M81. These data were obtained over a total of 20 HST orbits,...
The Star Formation Histories of Disk and E/S0 Galaxies from Resolved Stars (2009)
Olsen, Knut A. G., Romanowsky, Aaron J., Saha, Abhijit, Skillman, Evan, Williams, Benjamin F., Wyse, Rosemary F. G.
The resolved stellar populations of local galaxies, from which it is possible to derive complete star formation and chemical enrichment histories, provide an important way to study galaxy formation...
The Detection of Inside-out Disk Growth in M33 (2009)
Williams, Benjamin F., Dalcanton, Julianne J., Dolphin, Andrew E., Holtzman, Jon, Sarajedini, Ata
We present resolved stellar photometry of 4 fields along the major axis of the M33 disk from images taken with the Advanced Camera for Surveys aboard the Hubble Space Telescope. The photometry...
Detection of the second eclipsing high-mass X-ray binary in M 33 (2009)
Pietsch, Wolfgang, Haberl, Frank, Gaetz, Terrance J., Hartman, Joel D., Plucinsky, Paul P., Tüllmann, Ralph, ...
The ACS Nearby Galaxy Survey Treasury I. The Star Formation History of the M81 Outer Disk (2008)
Williams, Benjamin F., Dalcanton, Julianne J., Seth, Anil C., Weisz, Daniel, Dolphin, Andrew, Skillman, Evan, ...
The ACS Nearby Galaxy Survey Treasury (ANGST) is a large Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) treasury program to obtain resolved stellar photometry for a volume-limited...
Gogarten, Stephanie M., Dalcanton, Julianne J., Williams, Benjamin F., Seth, Anil C., Dolphin, Andrew, Weisz, Daniel, ...
We have obtained resolved stellar photometry from Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) observations of a field in the outer disk of M81 as part of the ACS Nearby Galaxy...
The Chandra ACIS Survey of M33 (ChASeM33): Transient X-ray Sources Discovered in M33 (2008)
Williams, Benjamin F., Gaetz, Terrance J., Haberl, Frank, Pietsch, Wolfgang, Shporer, Avi, Ghavamian, Parviz, ...
The Chandra ACIS Survey of M33 (ChASeM33) has acquired 7 fields of ACIS data covering M33 with 200 ks of exposure in each field. A catalog from the first 10 months of data, along with archival...
The Chandra ACIS survey of M33 (ChASeM33): transient X-ray sources discovered in M33 (2008)
Williams, Benjamin F., Gaetz, Terrance J., Haberl, Frank, Pietsch, Wolfgang, Shporer, Avi, Ghavamian, Parviz, ...
Virgo's intracluster globular clusters as seen by the advanced camera for surveys (2007)
Williams, Benjamin F., Ciardullo, Robin, Durrell, Patrick R., Feldmeier, John J., Sigurdsson, Steinn, Vinciguerra, Matt, ...
The metallicity distribution of intracluster stars in Virgo (2007)
Williams, Benjamin F., Ciardullo, Robin, Durrell, Patrick R., Vinciguerra, Matt, Feldmeier, John J., Jacoby, George H., ...
The resolved stellar populations of a dwarf spheroidal galaxy in the Virgo cluster (2007)
Durrell, Patrick R., Williams, Benjamin F., Ciardullo, Robin, Feldmeier, John J., Von Hippel, Ted, Sigurdsson, Steinn, ...
The Resolved Stellar Populations of a Dwarf Spheroidal Galaxy in the Virgo Cluster (2006)
Durrell, Patrick R., Williams, Benjamin F., Ciardullo, Robin, Feldmeier, John J., Von Hippel, Ted, Sigurdsson, Steinn, ...
We report on the discovery of a faint (M_V ~ -10.6 +/- 0.2) dwarf spheroidal galaxy on deep F606W and F814W Hubble Space Telescope images of a Virgo intracluster field. The galaxy is easily resolved...
The Metallicity Distribution of Intracluster Stars in Virgo (2006)
Williams, Benjamin F., Ciardullo, Robin, Durrell, Patrick R., Vinciguerra, Matt, Feldmeier, John J., Jacoby, George H., ...
We have used the Hubble Space Telescope's Advanced Camera for Surveys (ACS) to detect and measure ~5300 stars in a single intracluster field in the Virgo Cluster. By performing F606W and F814W...
Virgo's Intracluster Globular Clusters as Seen by the Advanced Camera for Surveys (2006)
Williams, Benjamin F., Ciardullo, Robin, Durrell, Patrick R., Feldmeier, John J., Sigurdsson, Steinn, Vinciguerra, Matt, ...
We report the discovery of 4 candidate intracluster globular clusters (IGCs) in a single deep HST ACS field of the Virgo Cluster. We show that each cluster is roughly spherical, has a magnitude near...
A Catalog of Transient X-ray Sources in M31 (2006)
Williams, Benjamin F., Naik, S., Garcia, Michael R., Callanan, Paul J.
From October 1999 to August 2002, 45 transient X-ray sources were detected in M31 by Chandra and XMM-Newton. We have performed spectral analysis of all XMM-Newton and Chandra ACIS detections of these...
A potential supernova remnant-x-ray binary association in M31 (2005)
Williams, Benjamin F., Barnard, Robin, Garcia, Michael R., Kolb, U., Osborne, J.P., Kong, Albert K.H.
The well-studied X-ray/optical/radio supernova remnant (SNR) DDB 1-15 (CXOM31 J004327.8+411829; r3-63) in M31 has been investigated with archival XMM-Newton and Chandra observations. The timing data...
A Soft X-ray Transient in the M31 Bulge (2005)
Williams, Benjamin F., Garcia, Michael R., McClintock, Jeffrey E., Primini, Frank A., Murray, Stephen S.
We have examined a probable soft X-ray transient source in the M31 bulge at R.A.=0:42:41.814 +/- 0.08", Dec. = 41:16:35.86 +/- 0.07". On the three occasions we observed the source, its spectrum was...
Chandra and Hubble Study of a New Transient X-ray Source in M31 (2005)
Williams, Benjamin F., Garcia, Michael R., McClintock, Jeffrey E., Primini, Frank A., Murray, Stephen S.
We present X-ray and optical observations of a new transient X-ray source in M31 first detected 23-May-2004 at R.A.=00:43:09.940 +/- 0.65'', Dec.=41:23:32.49 +/- 0.66''. The X-ray lightcurve shows...
A Potential Supernova Remnant/X-ray Binary Association in M31 (2005)
Williams, Benjamin F., Barnard, Robin, Garcia, Michael R., Kolb, U., Osborne, J. P., Kong, Albert K. H.
The well-studied X-ray/Optical/Radio supernova remnant DDB 1-15 (CXOM31 J004327.8+411829; r3-63) in M31 has been investigated with archival XMM-Newton and Chandra observations. The timing data from...
Optical Constraints on an X-ray Transient Source in M31 (2005)
Williams, Benjamin F., Garcia, Michael R., Primini, Frank A., McClintock, Jeffrey E., Murray, Stephen S.
We have detected a transient X-ray source in the M31 bulge through a continuing monitoring campaign with the Chandra ACIS-I camera. The source was detected at R.A.=00:42:33.428 +/- 0.11'',...
An X-ray Transient and Optical Counterpart in the M31 Bulge (2005)
Williams, Benjamin F., Garcia, Michael R., McClintock, Jeffrey E., Kong, Albert K. H., Primini, Frank A., Murray, Stephen S.
We have obtained snapshot images of a transient X-ray source in M31 from Chandra ACIS-I and the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The Chandra position of the X-ray nova...
Variable Star Candidates in an ACS Field of M31 (2005)
A search for variable stars is performed using two epochs of Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) imaging data for a 9.28 square arcminute portion of M31. This data set...
Discovery of an X-ray Nova in M31 (2004)
Williams, Benjamin F., Garcia, Michael R., Kong, Albert K. H., Primini, Frank A., Murray, Stephen S.
We have obtained snapshot images of an X-ray nova in M31 from Chandra ACIS-I and the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The Chandra position of the X-ray nova was...
Why are X-ray sources in the M31 Bulge so close to Planetary Nebulae? (2004)
Williams, Benjamin F., Garcia, Michael R., McClintock, Jeffrey E., Kong, Albert K. H.
We compare a deep (37 ks) Chandra ACIS-S image of the M31 bulge to deep [O III] Local Group Survey data of the same region. Through precision image alignment using globular cluster X-ray sources, we...
Imaging and Demography of the Host Galaxies of High-Redshift Type Ia Supernovae (2003)
Williams, Benjamin F., Hogan, Craig J., Barris, Brian, Candia, Pablo, Challis, Peter, Clocchiatti, Alejandro, ...
We present the results of a study of the host galaxies of high redshift Type Ia supernovae (SNe Ia). We provide a catalog of 18 hosts of SNe Ia observed with the Hubble Space Telescope (HST) by the...
A Synoptic X-ray Study of M31 with the Chandra-HRC (2003)
Williams, Benjamin F., Garcia, Michael R., Kong, Albert K. H., Primini, Frank A., King, A. R., Di Stefano, Rosanne, ...
We have obtained 17 epochs of Chandra High Resolution Camera (HRC) snapshot images, each covering most of the M31 disk. The data cover a total baseline of 2.5 years and contain a mean effective...
The Recent Star Formation History of the M31 Disk (2003)
The star formation history of the northern and southern M31 disk is measured using samples of BV photometry for 4' X 4' regions taken from the KPNO/CTIO Local Group Survey (Massey et al. 2001). The...
Comparing Young Stellar Populations Across Active Regions in the M31 Disk (2002)
I present preliminary BV resolved stellar photometry of the M31 disk measured from the data set of the NOAO/CTIO Local Group Survey. I have performed detailed analyses of the star formation histories...
Thesis (Ph. D.)--University of Washington, 2002.
Clues about the Star Formation History of the M31 Disk from WFPC2 Photometry (2001)
Over the past several years, the Hubble Space Telescope (HST) has acquired many broad-band images of various regions in the M31 disk. I have obtained 27 such fields from the HST data archive in order...
Identification and Analysis of Young Star Cluster Candidates in M31 (2001)
Williams, Benjamin F., Hodge, Paul W.
We present a method for finding clusters of young stars in M31 using broadband WFPC2 data from the HST data archive. Applying our identification method to 13 WFPC2 fields, covering an area of ~60...
WFPC2 Observations of Massive and Compact Young Star Clusters in M31 (2000)
Williams, Benjamin F., Hodge, Paul W.
We present color magnitude diagrams of four blue massive and compact star clusters in M31: G38, G44, G94, and G293. The diagrams of the four clusters reveal a well-populated upper main sequence and...
Mapping Low-Density Intergalactic Gas: a Third Helium Lyman-alpha Forest (1998)
Anderson, Scott F., Hogan, Craig J., Williams, Benjamin F., Carswell, Robert F.
We present a new HST/STIS spectrum of the z=3.18 quasar PKS 1935-692 and summarize the spectral features shortwards of 304A in the rest frame likely to be caused by foreground HeII Lyman-alpha...
Thesis (Ed.D.)--University of Tennessee.